samedi 19 mars 2016

NASA astronaut Jeff Williams is now the first American to become a three-time, long-term resident of the International Space Station. He arrived at the orbiting laboratory at 11:09 p.m. EDT Friday, with cosmonauts Alexey Ovchinin and Oleg Skripochka of the Russian space agency Roscosmos, where they will continue important research that advances NASA's Journey to Mars.

The trio launched aboard a Soyuz TMA-20M spacecraft from the Baikonur Cosmodrome in Kazakhstan at 5:26 p.m. (3:26 a.m. Saturday, March 19, Baikonur time), orbited Earth four times, and docked at the station. The hatches between the spacecraft and station opened at 12:55 a.m. Saturday, March 19.

Expedition 47 48 Crew Docks to the Space Station

The arrival of Williams, Ovchinin and Skripochka returns the station's crew complement to six. The three join Expedition 47 Commander Tim Kopra of NASA and Flight Engineers Tim Peake of ESA (European Space Agency) and Yuri Malenchenko of Roscosmos. The Expedition 47 crew members will spend five months conducting more than 250 science investigation in fields that benefit all of humanity, such as biology, Earth science, human research, physical sciences and technology development.

Image above: Expedition 47 crew members Flight Engineer Jeff Williams of NASA, Soyuz Commander Alexey Ovchinin of the Russian space agency Roscosmos, and Flight Engineer Oleg Skripochka of Roscosmos pose for a photo at the conclusion of a press conference on Thursday, March 17, 2016, at the Cosmonaut Hotel in Baikonur, Kazakhstan. Image Credits: NASA/Aubrey Gemignani.

Investigations arriving on Orbital ATK’s fifth NASA-contracted commercial resupply mission in late March will include a study of realistic fire scenarios on a spacecraft, enable the first space-based observations of meteors entering Earth’s atmosphere from space, explore how regolith, or soil, behaves and moves in microgravity, test a gecko-inspired adhesive gripping device that can stick on command in the harsh environment of space, and add a new 3-D printer for use on station.

Expedition 47 crew members also are expected to receive the first expandable habitat, which will allow NASA its first test of an innovative habitat concept that can support astronauts who live and work in the harsh environment of space. The Bigelow Expandable Activity Module (BEAM) is an experimental expandable module scheduled for delivery on SpaceX’s eighth NASA-contracted cargo resupply mission this spring. Although astronauts will not live in BEAM, it will be attached to the space station, expanded and tested for a minimum two-year demonstration, and crew members will enter periodically to evaluate performance of the habitat.

NASA is considering the use of expandable habitats to support crew members traveling to an asteroid, Mars and other destinations. An expandable habitat such as BEAM takes up less room on a rocket, while allowing additional volume for living and working in space.

The crew members also are scheduled to receive one Russian Progress resupply mission delivering about three tons of food, fuel, supplies and research.

Image above: The Soyuz TMA-20M rocket launches from the Baikonur Cosmodrome in Kazakhstan on Saturday, March 19, 2016 carrying Expedition 47 Soyuz Commander Alexey Ovchinin of the Russian space agency Roscosmos, Flight Engineer Jeff Williams of NASA, and Flight Engineer Oleg Skripochka of Roscosmos into orbit to begin their five and a half month mission on the International Space Station. Image Credits: NASA/Aubrey Gemignani.

During his six-month mission, Williams will become the American record holder for cumulative days in space -- 534 -- surpassing Expedition 46 Commander Scott Kelly, who wrapped up his one-year mission March 1. Williams will take command of the station on June 4 for Expedition 48. Williams, Ovchinin and Skripochka will remain aboard the station until early September 2016. Kopra, Peake and Malenchenko will return to Earth on June 5.

For 15 years, humans have been living continuously aboard the International Space Station to advance scientific knowledge and demonstrate new technologies, making research breakthroughs not possible on Earth and that will enable long-duration human and robotic exploration into deep space. A truly global endeavor, more than 200 people from 15 countries have visited the unique microgravity laboratory that has hosted more than 1,700 research investigations from researchers in more than 83 countries.

vendredi 18 mars 2016

Image above: The Soyuz TMA-20M spacecraft launches on time from the Baikonur Cosmodrome in Kazakhstan. Image Credit: NASA TV.

The Soyuz TMA-20M launched from the Baikonur Cosmodrome in Kazakhstan to the International Space Station at 5:26 p.m. EDT Friday (3:26 a.m. on March 19 in Baikonur). Jeff Williams of NASA and Roscosmos cosmonauts Oleg Skripochka and Alexey Ovchinin are now safely in orbit.

NASA astronaut Jeff Williams and Roscosmos cosmonauts Oleg Skripochka and Alexey Ovchinin are on the way to the International Space Station (ISS) for a six hours flight.

The trio will join Expedition 47 Commander Tim Kopra of NASA and Flight Engineers Tim Peake of ESA (European Space Agency) and cosmonaut Yuri Malenchenko of Roscosmos. Together, they will bring the total to six crew aboard station, which will once again be fully staffed after operating with only three crew members following the departure of a separate trio on March 1.

During his six-month mission, Williams will become the new American record holder for cumulative days in space – 534 – surpassing Expedition 46 Commander Scott Kelly, who wrapped up his one-year mission on March 1. Williams will take command of the station on June 4 for Expedition 48. This will be his third space station expedition – another record.

The Expedition 47 crew members will continue several hundred experiments in biology, biotechnology, physical science and Earth science currently underway and scheduled to take place aboard humanity’s only orbiting laboratory. Williams, Ovchinin and Skripochka are scheduled to spend six months on the station, returning to Earth in early September 2016.

SpaceX plans to launch its Dragon spacecraft into orbit in early April, the company’s eighth mission under NASA’s Commercial Resupply Services contract, CRS-8. The flight will deliver research experiments to the International Space Station that will help investigators test the use of an expandable space habitat in microgravity, assess the impact of antibodies on muscle wasting in a microgravity environment, use microgravity to seek insight into the interactions of particle flows at the nanoscale level and use protein crystal growth in microgravity to help in the design of new drugs to fight disease. Investigations like these demonstrate how the orbiting laboratory helps advance NASA's journey to Mars while making discoveries off the Earth that can benefit life on Earth.

Future space habitats for low-Earth orbit or in deep space should be lightweight and relatively simple to construct. The Bigelow Expandable Activity Module (BEAM) is an experimental expandable capsule that attaches to the space station. After installation, the BEAM expands to roughly 13-feet-long and 10.5 feet in diameter to provide a large volume, where a crew member can enter. During the two-year test mission, astronauts will enter the module for a few hours three-to-four times a year to retrieve sensor data and conduct assessments of the module’s condition.

Expandable habitats greatly decrease the amount of transport volume at launch for future space missions. These “expandables” take up less room on a rocket, but once set up, provide greatly enhanced space for living and working. They also may protect against solar radiation, and be an additional barrier protecting the crew from space debris and other contaminants; however, testing needs to be done on the design performance of expandables. BEAM provides a test platform for demonstrating the thermal, structural, mechanical durability, radiation protection performance, and long-term leak performance of expandable habitats.

The BEAM will be installed via the Canadarm2, which will remove the module from the capsule and connect it to the rear port of the space station’s Node 3. The module will be expanded at a later date.

Research supplies launching on this mission also will help scientists continue to study spaceflight risks that have been identified, but not solved. For instance, we now know that spaceflight causes a rapid loss of bone and muscle mass especially in the legs and spine, similar to the rate of atrophy seen in people with muscle-wasting diseases or with limited mobility on Earth. The Rodent Research-3-Eli Lilly investigation will assess myostatin inhibition for preventing skeletal muscle atrophy and weakness in mice exposed to long-duration spaceflight. The investigation is sponsored by pharmaceutical company Eli Lilly and Co. and the Center for the Advancement of Science in Space (CASIS) and studies molecular and physical changes in the musculoskeletal system that happen in space.

Image above: The BEAM module will be attached to the rear port of the space station’s Node 3. After installation, the BEAM expands to roughly 13-feet-long and 10.5 feet in diameter. Image Credits: Bigelow Aerospace, LLC.

Crew members experience significant decreases in their bone density and muscle mass during spaceflight if they do not get enough exercise during long- duration missions. These effects are most obvious in the body parts that bear weight on the ground, especially the legs, hips and spine. This investigation uses mice as a model for human health to study whether certain drugs might prevent muscle or bone loss while in microgravity. Mice also experience bone and muscle loss in space, and are a potentially valuable model for spaceflight-induced musculoskeletal disuse atrophy. The results could expand scientists’ understanding of muscle atrophy and bone loss in space, by testing an antibody that has been known to prevent muscle wasting in mice on Earth.

Ultimately, drugs tested on the space station could progress to terrestrial human clinical trials, and would be validated for use on future space missions to maintain crew members’ physical health during long-duration missions.

Numerous diseases or physical impairments cause bone and muscle loss, including muscular dystrophy, cancer, spinal cord injury and the aging process. Patients on extended bed rest also experience similar physical changes. Results from this investigation could lead to new treatments for bone- and muscle-wasting diseases on Earth.

Image above: Astronaut Scott Kelly is photographed working with the Microgravity Sciences Glovebox (MSG) during a separate CASIS Rodent Research session using the Bone Densitometer Image Credit: NASA.

While investigations using model organisms like mice could benefit medicine on Earth, medicine, biology, computer science and many other fields benefit from nanotechnology. Nanoscience and nanotechnology are the study and application of exceptionally small things and can be used across the fields of medicine, biology, computer science and many others. Fluid dynamics are very different on this small scale, so scientists want to know how microparticles might interact more with surfaces of channels than with each other. This is the goal of the Microchannel Diffusion investigation.

Nanofluidic studies like Microchannel Diffusion are the study of fluids at the nanoscale, or the atomic level, and hold promise for a wide range of technologies. Nanofluidic sensors could measure the air in the space station, or be used to deliver drugs to specific places in the body, among other potential uses. But the laws that govern flow through nanoscale channels are not well understood. This investigation simulates these interactions by studying them at a larger scale, the microscopic level. This is only possible on the orbiting laboratory, where Earth’s gravity is not strong enough to interact with the molecules in a sample, so they behave more like they would at the nanoscale. Knowledge gleaned from the investigation may have implications for drug delivery, particle filtration and future technological applications for space exploration.

The CASIS Protein Crystal Growth 4 (CASIS PCG 4) investigation also has applications in medicine, specifically drug design and development. CASIS PCG 4 comprises two investigations that both leverage the microgravity environment in the growth of protein crystals and focus on structure-based drug design (SBDD). SBDD is an integral component in the drug discovery and development process. Primarily, SBDD relies on the three-dimensional, structural information provided by protein crystallography to inform the design of more potent, effective and selective drugs.

It has been established that growing protein crystals in microgravity can avoid some of the obstacles inherent to protein crystallization on Earth, such as sedimentation. One investigation will study the effect of microgravity on the co-crystallization of a membrane protein with a medically relevant compound in microgravity in order to determine its three-dimensional structure. This will enable scientists to chemically target and inhibit, with “designer” compounds, an important human biological pathway that has been shown to responsible for several types of cancer.

The second investigation, A Co-Crystallization in Microgravity Approach to Structure-based Drug Design, seeks to determine whether crystals formed in microgravity represent an improvement over crystals formed by ground-based methods. Scientists expect the crystals formed in microgravity to diffract to a higher resolution than those developed on Earth, and thereby, provide greater molecular detail. This will permit more confident evaluations of ligand-binding (when a signal-triggering molecule binds to a site on a target protein). The resulting structures could be used to advance the medical-chemistry effort through improved/enhanced SBDD.

Two comets that will safely fly past Earth later this month may have more in common than their intriguingly similar orbits. They may be twins of a sort.

Comet P/2016 BA14 was discovered on Jan. 22, 2016, by the University of Hawaii's PanSTARRS telescope on Haleakala, on the island of Maui. It was initially thought to be an asteroid, but follow-up observations by a University of Maryland and Lowell Observatory team with the Discovery Channel Telescope showed a faint tail, revealing that the discovery was, in fact, a comet. The orbit of this newly discovered comet, however, held yet another surprise. Comet P/2016 BA14 follows an unusually similar orbit to that of comet 252P/LINEAR, which was discovered by the Massachusetts Institute of Technology's Lincoln Near Earth Asteroid Research (LINEAR) survey on April 7, 2000. The apparent coincidence may be an indication of twin nature in that comet. P/2016 BA14 is roughly half the size of comet ?252P/LINEAR and might be a fragment that calved off sometime in the larger comet's past.

"Comet P/2016 BA14 is possibly a fragment of 252P/LINEAR. The two could be related because their orbits are so remarkably similar," said Paul Chodas, manager of NASA's Center of NEO Studies (CNEOS) at the Jet Propulsion Laboratory in Pasadena, California. "We know comets are relatively fragile things, as in 1993 when comet Shoemaker-Levy 9 was discovered and its pieces linked to a flyby of Jupiter. Perhaps during a previous pass through the inner-solar system, or during a distant flyby of Jupiter, a chunk that we now know of as BA14 might have broken off of 252P."

Image above: Comet 252P/LINEAR will safely fly past Earth on March 21, 2016, at a range of about 3.3 million miles (5.2 million kilometers). The following day, comet P/2016 BA14 will safely fly by our planet at a distance of about 2.2 million miles (3.5 million kilometers). Image credits: NASA/JPL-Caltech.

Observations made by the Hubble Space Telescope of comet 252P/LINEAR, and by NASA's Infrared Telescope Facility of comet P/2016 BA14 will further investigate their possible twin nature.

Comet 252P/LINEAR, approximately 750 feet (230 meters) in size, will zip past Earth on Monday, March 21 at a range of about 3.3 million miles (5.2 million kilometers). The following day, comet P/2016 BA14 will safely fly by our planet at a distance of about 2.2 million miles (3.5 million kilometers). This will be the third closest flyby of a comet in recorded history next to comet D/1770 L1 (Lexell) in 1770 and comet C/1983 H1 (IRAS-Araki-Alcock) in 1983.

The time of closest approach for comet 252P/LINEAR on March 21 will be around 5:14 a.m. PDT (8:14 a.m. EDT). The time of closest approach for P/2016 BA14 on March 22 will be around 7:30 a.m. PDT (10:30 a.m. EDT). While both comets will safely fly past at relatively close distances, anyone hoping to see them will need powerful, professional-grade telescopes, due to their relatively small size.

The approaches of these two comets will be the closest they come to Earth for the foreseeable future. "March 22 will be the closest comet P/2016 BA14 gets to us for at least the next 150 years," said Chodas. "Comet P/2016 BA14 is not a threat. Instead, it is an excellent opportunity for scientific advancement on the study of comets."

The CNEOS website has a complete list of recent and upcoming close approaches, as well as all other data on the orbits of known NEOs, so scientists and members of the media and public can track information on known objects.

jeudi 17 mars 2016

Images above: Three examples of super spirals are presented here in images taken by the Sloan Digital Sky Survey. Images Credit: SDSS.

A strange new kind of galactic beast has been spotted in the cosmic wilderness. Dubbed "super spirals," these unprecedented galaxies dwarf our own spiral galaxy, the Milky Way, and compete in size and brightness with the largest galaxies in the universe.

Super spirals have long hidden in plain sight by mimicking the appearance of typical spiral galaxies. A new study using archived NASA data reveals these seemingly nearby objects are in fact distant, behemoth versions of everyday spirals. Rare, super spiral galaxies present researchers with the major mystery of how such giants could have arisen.

"We have found a previously unrecognized class of spiral galaxies that are as luminous and massive as the biggest, brightest galaxies we know of," said Patrick Ogle, an astrophysicist at the Infrared Processing and Analysis Center (IPAC) at the California Institute of Technology in Pasadena and lead author of a new paper on the findings published in The Astrophysical Journal. "It's as if we have just discovered a new land animal stomping around that is the size of an elephant but had shockingly gone unnoticed by zoologists."

Image Credit: SDSS

Ogle and colleagues chanced upon super spirals as they searched for extremely luminous, massive galaxies in the NASA/IPAC Extragalactic Database (NED), an online repository containing information on over 100 million galaxies. NED brings together a wealth of data from many different projects, including ultraviolet light observations from the Galaxy Evolution Explorer, visible light from Sloan Digital Sky Survey, infrared light from the Two Micron All-Sky Survey, and links to data from other missions such as Spitzer and the Wide-ﬁeld Infrared Survey Explorer, or WISE.

"Remarkably, the finding of super spiral galaxies came out of purely analyzing the contents of the NASA/IPAC Extragalactic Database, thus reaping the benefits of the careful, systematic merging of data from many sources on the same galaxies," said George Helou, a study co-author and the executive director of IPAC. "NED is surely holding many more such nuggets of information, and it is up to us scientists to ask the right questions to bring them out."

Ogle, Helou and their colleagues expected that humongous, mature galaxies called ellipticals -- so named for their football-like shapes -- would dominate their search within NED for the most luminous galaxies. But a tremendous surprise lay in store for the scientists.

Image Credit: SDSS

In a sample of approximately 800,000 galaxies no more than 3.5 billion light-years from Earth, 53 of the brightest galaxies intriguingly had a spiral, rather than elliptical, shape. The researchers double-checked the distances to the spiral galaxies and saw that none were nearby -- even the closest lay some 1.2 billion light-years away. With the correct distance estimates in hand, the stunning properties of this newfound batch of whirlpool-shaped galaxies came to light.

Super spirals can shine with anywhere from eight to 14 times the brightness of the Milky Way. They possess as much as 10 times our galaxy's mass. Their gleaming, starry disks stretch from twice to even four times the width of the Milky Way galaxy's approximately 100,000 light-year-wide disk, with the largest super spiral spanning a whopping 440,000 light-years. Super spirals also give off copious ultraviolet and mid-infrared light, signifying a breakneck pace of churning out new stars. Their star formation rate is as high as 30 times that of our own run-of-the-mill galaxy.

According to established astrophysical theory, spiral galaxies should not be able to attain any of these feats because their size and star-making potential are limited. As spiral galaxies grow by gravitationally attracting fresh, cool gas from intergalactic space, their masses reach a tipping point in which any newly captured gas rushes in too rapidly. This headlong gas heats up and prevents subsequent star formation in a process known as "quenching." Bucking this conventional wisdom, though, super spirals remain unquenched.

Image Credit: SDSS

A vital hint about the potential origin of super spirals is that four out of the 53 seen by Ogle and colleagues clearly contain two galactic nuclei, instead of just one as usual. Double nuclei, which look like two egg yolks frying in a pan, are a telltale sign of two galaxies having just merged together. Conventionally, mergers of spiral galaxies are destined to become bloated, elliptical galaxies. Yet Ogle and colleagues speculate that a special merger involving two, gas-rich spiral galaxies could see their pooled gases settle down into a new, larger stellar disk -- presto, a super spiral.

"Super spirals could fundamentally change our understanding of the formation and evolution of the most massive galaxies," said Ogle. "We have much to learn from these newly identified, galactic leviathans."

Other authors of the new study are Lauranne Lanz of IPAC and Cyril Nader, an undergraduate student at the University of California, Los Angeles, who worked on this project during a summer internship at IPAC.

This image of haze layers above Pluto’s limb was taken by the Ralph/Multispectral Visible Imaging Camera (MVIC) on NASA’s New Horizons spacecraft. About 20 haze layers are seen; the layers have been found to typically extend horizontally over hundreds of kilometers, but are not strictly parallel to the surface. For example, scientists note a haze layer about 3 miles (5 kilometers) above the surface (lower left area of the image), which descends to the surface at the right.

This week, in the journal Science, New Horizons scientists have authored the first comprehensive set of papers describing results from last summer’s Pluto system flyby. Above the surface, scientists discovered Pluto’s atmosphere contains layered hazes, and is both cooler and more compact than expected. This affects how Pluto’s upper atmosphere is lost to space, and how it interacts with the stream of charged particles from the sun known as the solar wind.

Astronomers using the unique ultraviolet capabilities of the NASA/ESA Hubble Space Telescope have identified nine monster stars with masses over 100 times the mass of the Sun in the star cluster R136. This makes it the largest sample of very massive stars identified to date. The results, which will be published in the Monthly Notices of the Royal Astronomical Society, raise many new questions about the formation of massive stars.

R136 observed with WFC3

An international team of scientists using the NASA/ESA Hubble Space Telescope has combined images taken with the Wide Field Camera 3 (WFC3) with the unprecedented ultraviolet spatial resolution of the Space Telescope Imaging Spectrograph (STIS) to successfully dissect the young star cluster R136 in the ultraviolet for the first time [1].

R136 is only a few light-years across and is located in the Tarantula Nebula within the Large Magellanic Cloud, about 170 000 light-years away. The young cluster hosts many extremely massive, hot and luminous stars whose energy is mostly radiated in the ultraviolet [2]. This is why the scientists probed the ultraviolet emission of the cluster.

As well as finding dozens of stars exceeding 50 solar masses, this new study was able to reveal a total number of nine very massive stars in the cluster, all more than 100 times more massive as the Sun. However, the current record holder R136a1 does keep its place as the most massive star known in the Universe, at over 250 solar masses. The detected stars are not only extremely massive, but also extremely bright. Together these nine stars outshine the Sun by a factor of 30 million.

The scientists were also able to investigate outflows from these behemoths, which are most readily studied in the ultraviolet. They eject up to an Earth mass of material per month at a speed approaching one percent of the speed of light, resulting in extreme weight loss throughout their brief lives.

“The ability to distinguish ultraviolet light from such an exceptionally crowded region into its component parts, resolving the signatures of individual stars, was only made possible with the instruments aboard Hubble,” explains Paul Crowther from the University of Sheffield, UK, and lead author of the study. “Together with my colleagues, I would like to acknowledge the invaluable work done by astronauts during Hubble’s last servicing mission: they restored STIS and put their own lives at risk for the sake of future science!” [3]

Pseudo image of R136

In 2010 Crowther and his collaborators showed the existence of four stars within R136, each with over 150 times the mass of the Sun. At that time the extreme properties of these stars came as a surprise as they exceeded the upper-mass limit for stars that was generally accepted at that time. Now, this new census has shown that there are five more stars with more than 100 solar masses in R136. The results gathered from R136 and from other clusters also raise many new questions about the formation of massive stars as the origin of these behemoths remains unclear [4].

Saida Caballero-Nieves, a co-author of the study, explains: “There have been suggestions that these monsters result from the merger of less extreme stars in close binary systems. From what we know about the frequency of massive mergers, this scenario can’t account for all the really massive stars that we see in R136, so it would appear that such stars can originate from the star formation process.”

In order to find answers about the origin of these stars the team will continue to analyse the gathered datasets. An analysis of new optical STIS observations will also allow them to search for close binary systems in R136, which could produce massive black hole binaries which would ultimately merge, producing gravitational waves.

Hubble and the sunrise over Earth

“Once again, our work demonstrates that, despite being in orbit for over 25 years, there are some areas of science for which Hubble is still uniquely capable,” concludes Crowther.

Notes:

1] R136 was originally listed in a catalogue of the brightest stars in the Magellanic Clouds compiled at the Radcliffe Observatory in South Africa. It was separated into three components a, b, c at the European Southern Observatory, with R136a subsequently resolved into a group of eight stars (a1-a8) at ESO, and confirmed as a dense star cluster with the NASA/ESA Hubble Space Telescope after the first servicing mission in 1993.

[2] Very massive stars are exclusive to the youngest star clusters because their lifetimes are only 2-3 million years. Only a handful of such stars are known in the entire Milky Way galaxy.

[3] STIS’s capabilities were restored in 2009 by astronauts who successfully completed Serving Mission 4 (SM4), one of the Hubble’s most challenging and intense servicing missions, involving five spacewalks.

[4] The ultraviolet signatures of even more very massive stars have also been revealed in other clusters — examples include star clusters in the dwarf galaxies NGC 3125 and NGC 5253. However, these clusters are too distant for individual stars to be distinguished even with Hubble.

More information:

The Hubble Space Telescope is a project of international cooperation between ESA and NASA.

The results were published in the paper “The R136 star cluster dissected with Hubble Space Telescope/STIS. I. Far-ultraviolet spectroscopic census and the origin of Heii λ1640 in young star clusters” in the Monthly Notices of the Royal Astronomical Society.

mercredi 16 mars 2016

Image above: Sea level anomalies from February 12-22, 2016. The U.S./European Jason-3 satellite has produced its first map of sea surface height, which corresponds well to data from its predecessor, Jason-2. Higher-than-normal sea levels are red; lower-than-normal sea levels are blue. El Nino is visible as the red blob in the eastern equatorial Pacific.Image Credits: NASA/JPL Ocean Surface Topography Team.

Jason-3, a new U.S.-European oceanography satellite mission with NASA participation, has produced its first complete science map of global sea surface height, capturing the current signal of the 2015-16 El Niño.

The map was generated from the first 10 days of data collected once Jason-3 reached its operational orbit of 830 miles (1,336 kilometers) last month. It shows the state of the ongoing El Niño event that began early last year. After peaking in January, the high sea levels in the eastern Pacific are now beginning to shrink.

Launched Jan. 17 from California’s Vandenberg Air Force Base, Jason-3 is operated by the National Oceanic and Atmospheric Administration (NOAA) in partnership with NASA, the French Space Agency Centre National d’Etudes Spatiales (CNES) and the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT). Its nominal three-year mission will continue nearly a quarter-century record of monitoring changes in global sea level. These measurements of ocean surface topography are used by scientists to help calculate the speed and direction of ocean surface currents and to gauge the distribution of solar energy stored in the ocean.

Information from Jason-3 will be used to monitor climate change and track phenomena like El Niño. It will also enable more accurate weather, ocean and climate forecasts, including helping global weather and environmental agencies more accurately forecast the strength of tropical cyclones.

Jason-3 data will also be used for other scientific, commercial and operational applications, including monitoring of deep-ocean waves; forecasts of surface waves for offshore operators; forecasts of currents for commercial shipping and ship routing; coastal forecasts to respond to environmental challenges like oil spills and harmful algal blooms; and coastal modeling crucial for marine mammal and coral reef research.

“Jason-3 has big shoes to fill,” said Josh Willis, NASA project scientist for Jason-3 at NASA’s Jet Propulsion Laboratory in Pasadena, California. “By measuring the changing levels of the ocean, Jason-2 and its predecessors have built one of the clearest records we have of our changing climate.”

That record began with the 1992 launch of the NASA/CNES Topex/Poseidon mission (1992-2006) and was continued by Jason-1 (2001-2013); and Jason-2, launched in 2008 and still in operation. Data from Jason-3’s predecessor missions show that mean sea level has been rising by about 0.12 inches (3 millimeters) a year since 1993.

Over the past several weeks, mission controllers have activated and checked out Jason-3’s systems, instruments and ground segment, all of which are functioning properly. They also maneuvered Jason-3 into its operational orbit, where it now flies in formation with Jason-2 in the same orbit, approximately 80 seconds apart. The two satellites will make nearly simultaneous measurements over the mission’s six-month checkout phase to allow scientists to precisely calibrate Jason-3’s instruments.

John Lillibridge, NOAA Jason-3 project scientist in College Park, Maryland, said comparisons of data from the two satellites show very close agreement. “It’s really fantastic. The excellent agreement we already see with Jason-2 shows us that Jason-3 is working extremely well, right out of the box. This kind of success is only possible because of the collaboration that’s been developed between our four international agencies over the past quarter century.”

Jason-3 spacecraft. Image Credits: NASA/JPL

Once Jason-3 is fully calibrated and validated, it will begin full science operations, precisely measuring the height of 95 percent of the world’s ice-free ocean every 10 days and providing oceanographic products to users around the world. Jason-2 will then be moved into a new orbit, with ground tracks that lie halfway between those of Jason-3. This move will double coverage of the global ocean and improve data resolution for both missions. This interleaved mission will improve our understanding of ocean currents and eddies and provide better information for forecasting them throughout the global oceans.

NASA and CNES shared responsibilities for Jason-3’s satellite development and launch. CNES provided the Jason-3 spacecraft, while NASA was responsible for management of launch services and countdown operations for the SpaceX Falcon 9 rocket. NASA and CNES jointly provided the primary payload instruments. CNES and NOAA are responsible for satellite operations, with instrument operations support from JPL, which is managing the mission for NASA. Upon completion of Jason-3’s commissioning phase, CNES will hand over satellite mission operations and control to NOAA. Processing, archival and distribution of data products to users worldwide is being carried out by CNES, EUMETSAT and NOAA.

NASA uses the vantage point of space to increase our understanding of our home planet, improve lives and safeguard our future. NASA develops new ways to observe and study Earth's interconnected natural systems with long-term data records. The agency freely shares this unique knowledge and works with institutions around the world to gain new insights into how our planet is changing.

Observations made using the HARPS spectrograph at ESO’s La Silla Observatory in Chile have revealed unexpected changes in the bright spots on the dwarf planet Ceres. Although Ceres appears as little more than a point of light from the Earth, very careful study of its light shows not only the changes expected as Ceres rotates, but also that the spots brighten during the day and also show other variations. These observations suggest that the material of the spots is volatile and evaporates in the warm glow of sunlight.

Ceres is the largest body in the asteroid belt between Mars and Jupiter and the only such object classed as a dwarf planet. NASA’s Dawn spacecraft has been in orbit around Ceres for more than a year and has mapped its surface in great detail. One of the biggest surprises has been the discovery of very bright spots, which reflect far more light than their much darker surroundings [1]. The most prominent of these spots lie inside the crater Occator and suggest that Ceres may be a much more active world than most of its asteroid neighbours.

New and very precise observations using the HARPS spectrograph at the ESO 3.6-metre telescope at La Silla, Chile, have now not only detected the motion of the spots due to the rotation of Ceres about its axis, but also found unexpected additional variations suggesting that the material of the spots is volatile and evaporates in sunlight.

The bright spots on Ceres imaged by the Dawn spacecraft

The lead author of the new study, Paolo Molaro, at the INAF–Trieste Astronomical Observatory, takes up the story: "As soon as the Dawn spacecraft revealed the mysterious bright spots on the surface of Ceres, I immediately thought of the possible measurable effects from Earth. As Ceres rotates the spots approach the Earth and then recede again, which affects the spectrum of the reflected sunlight arriving at Earth.”

Ceres spins every nine hours and calculations showed that the effects due to the motion of the spots towards and away from the Earth caused by this rotation would be very small, of order 20 kilometres per hour. But this motion is big enough to be measurable via the Doppler effect with high-precision instruments such as HARPS.

The team observed Ceres with HARPS for a little over two nights in July and August 2015. "The result was a surprise," adds Antonino Lanza, at the INAF–Catania Astrophysical Observatory and co-author of the study. "We did find the expected changes to the spectrum from the rotation of Ceres, but with considerable other variations from night to night.”

Artist’s view of bright spots on Ceres imaged by the Dawn spacecraft

The team concluded that the observed changes could be due to the presence of volatile substances that evaporate under the action of solar radiation [2]. When the spots inside the Occator crater are on the side illuminated by the Sun they form plumes that reflect sunlight very effectively. These plumes then evaporate quickly, lose reflectivity and produce the observed changes. This effect, however, changes from night to night, giving rise to additional random patterns, on both short and longer timescales.

If this interpretation is confirmed Ceres would seem to be very different from Vesta and the other main belt asteroids. Despite being relatively isolated, it seems to be internally active [3]. Ceres is known to be rich in water, but it is unclear whether this is related to the bright spots. The energy source that drives this continual leakage of material from the surface is also unknown.

Dawn is continuing to study Ceres and the behaviour of its mysterious spots. Observations from the ground with HARPS and other facilities will be able to continue even after the end of the space mission.

The motions of the bright spots on Ceres

Notes:

[1] Bright spots were also seen, with much less clarity, in earlier images of Ceres from the NASA/ESA Hubble Space Telescope taken in 2003 and 2004.

[2] It has been suggested that the highly reflective material in the spots on Ceres might be freshly exposed water ice or hydrated magnesium sulphates.

[3] Many of the most internally active bodies in the Solar System, such as the large satellites of Jupiter and Saturn, are subjected to strong tidal effects due to their proximity to the massive planets.

More information:

This research was presented in a paper entitled “Daily variability of Ceres’ Albedo detected by means of radial velocities changes of the reflected sunlight”, by P. Molaro et al., which appeared in the journal Monthly Notices of the Royal Astronomical Society.

ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive ground-based astronomical observatory by far. It is supported by 16 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom, along with the host state of Chile. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world’s most advanced visible-light astronomical observatory and two survey telescopes. VISTA works in the infrared and is the world’s largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is a major partner in ALMA, the largest astronomical project in existence. And on Cerro Armazones, close to Paranal, ESO is building the 39-metre European Extremely Large Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.

Engineers building parts of a new type of power plant for generating green energy with nuclear fusion are using their expertise from building rockets like Europe’s Ariane 5 to create the super-strong structures to cope with conditions similar to those inside the Sun.

Nuclear fusion to generate green energy

A technique for building launcher and satellite components has turned out to be the best way for constructing rings to support the powerful magnetic coils inside the machine.

Meaning “the way” in Latin, the International Thermonuclear Experimental Reactor, ITER, is the world’s largest nuclear fusion experiment on generating electricity and is now being built in France.

Spanish company CASA Espacio is making the rings using a method they have perfected over two decades of building elements for the Ariane 5, Vega and Soyuz rockets, as well as for satellites and the International Space Station.

“Forces inside ITER present similar challenges to space,” explains Jose Guillamon, Head of Commercial and Strategy.

Ariane 5 liftoff

“We can’t use traditional materials like metal, which expand and contract with temperature and conduct electricity. We have to make a special composite material which is durable and lightweight, non-conductive and never changes shape.”

At their centre of excellence in Spain with its track record in composites for space applications, CASA Espacio has been at the forefront of developing a technique for embedding carbon fibres in resin to create a strong, lightweight material.

The composite is ideal for rocket parts because it retains its shape and offers the robust longevity needed to survive extreme launches and the harsh environment of space for over 15 years.

Pre-compression rings

Now, the team is using a similar technique to build the largest composite structures ever attempted for a cryogenic environment. With a diameter of 5 m and a solid cross-section of 30x30 cm, ITER’s compression rings will hold the giant magnets in place.

Harnessing star energy

Nuclear fusion powers the Sun and stars, with hydrogen atoms colliding to form helium while releasing energy. It has long been a dream to harness this extreme process to generate an endless supply of sustainable electricity from seawater and Earth’s crust.

In a worldwide research collaboration between China, the EU, India, Japan, South Korea, Russia and the US, the first prototype of its kind is now being realised in ITER.

Construction is expected to be completed by 2019 for initial trials as early as 2020. A commercial successor for generating electricity is not predicted before 2050.

ITER fly-through

Designed to generate 500 MW while using only a tenth of that to run, ITER aims to demonstrate continuous controlled fusion and, for the first time in fusion research, produce more energy than it takes to operate.

Inherently safe with no atmospheric pollution or long-lived radioactive waste, one kilogram of fuel could produce the same amount of energy as 10 000 tonnes of fossil fuel.

At ITER’s core is a doughnut-shaped magnetic chamber, 23 m in diameter. It will work by heating the electrically charged gases to more than 150 000 000ºC.

Hotter than the Sun, the plasma would instantly evaporate any normal container. Instead, giant electromagnets will hold the plasma away from the walls by suspending it within a magnetic ‘cage’.

Construction site

Building something that can withstand this powerful magnetic field is an extreme engineering challenge.

CASA Espacio had the answer thanks to their expertise and method for making space components.

Now under construction, ITER’s rings will each withstand 7000 tonnes – the equivalent of the Eiffel Tower pressing against each one of the six rings.

Cut the cloth to fit spacecraft

Carbon fibres are woven like fabric and embedded in a resin matrix to create a lightweight, durable and stable composite.

“In the same way that you’d weave a different fabric for a raincoat than you would for a summer shirt, we can lay the fibres in different directions and alter the ingredients to adapt the resulting material to its role, making it extra strong, for example, or resistant to extreme temperatures in space,” explains Jose.

Tokamak

For ITER, glass fibres are laid to maximise their mechanical strength and can be built up in slices and stacked like doughnuts to create the cylindrical structure.

“Space expertise can provide a tremendous resource to so many companies in non-space sectors, helping them to improve their product and increase their revenues,” says Richard Seddon from Tecnalia, worked with ESA´s Technology Transfer Network, which helps companies employ technologies from space to improve their businesses.

ITER construction

“In this case, CASA Espacio had just the right proven expertise to provide the best solution for ITER.”

mardi 15 mars 2016

Ninety years ago, on March 16, 1926, a rocket lifted off – not with a bang, but with a subtle, quiet flame – and forever changed the scope of scientific exploration. This event ties directly to the birth of NASA more than 30 years later.

Less than a century ago, astronomers relied entirely on ground-based observations to further scientific study. Today, descendants of that first liquid-fueled rocket provide eyes on cosmic phenomena, unravel mysteries of the early universe, and even take a closer look at what makes our own planet tick.

None of this would be possible without the experiments of Massachusetts physics professor Robert Goddard, best known for inventing the liquid-fueled rocket. The namesake of NASA’s Goddard Space Flight Center in Greenbelt, Maryland, he dreamed as early as 1909 of creating an interplanetary vehicle. While he couldn’t achieve that in his lifetime, his inventions in the first half of the 20th century became the engineering foundation for the rockets that first took humans to the moon in the 1960s and for today’s rockets, which look further into space than ever before.

Prior to Goddard’s experimentation, rockets had not changed much in several centuries. Chinese engineers invented them as war machines in the 13th century, using solid gunpowder as fuel. But Goddard realized that liquid propellants offered a number of advantages over solid-fueled rockets. He began to test rockets fueled by liquid gasoline and liquid oxygen.

The new design posed a number of challenges. For instance, he had to find a way to mix the fuel with oxygen. Otherwise it wouldn’t burn fast enough to produce the necessary thrust to lift the weight of the rocket. He also had to find a mechanical solution to pressurize the fuel chamber so it would continually feed fuel to the engine. Each solution he found brought with it a new challenge to solve.

After nearly 17 years of work, Goddard successfully launched his creation on March 16, 1926.

Image above: Robert Goddard stands next to his first liquid-fueled rocket prior to its launch on March 16, 1926. Image Credits: Clark University Robert H. Goddard Archive.

"It looked almost magical as it rose, without any appreciably greater noise or flame, as if it said, 'I've been here long enough; I think I'll be going somewhere else, if you don't mind,'" Goddard wrote in his journal the next day.

Most rockets today use liquid fuels because they provide more thrust per unit of fuel and they allow engineers to time how long the rocket will remain lit more precisely. For example, the Atlas V, on which many NASA missions launch – such as the Magnetospheric Multiscale Mission, which launched in 2015 – and the Ariane V, on which NASA’s James Webb Space Telescope will launch in 2018, both use liquid fuels in one or more of their stages.

Over the course of his career, as well as posthumously, Goddard was awarded more than 200 patents for his inventions, many of which pertained to rocketry. These also included the invention of multistage rockets, which contain multiple fuel tanks and engine segments that can be jettisoned as they are emptied.

Goddard’s work didn’t stop there. He continued to improve upon his rocket concepts until his death in 1945. The U.S. failed to recognize the full potential of his work until after his death – in fact, some of his ideas about reaching outer space were ridiculed during his lifetime. But the first liquid-fueled rocket flight was as significant to space exploration as the Wright brothers’ first flight was to air travel, and 90 years later, his patents are still integral to spaceflight technology.

This illustration lays a depiction of the sun's magnetic fields over an image captured by NASA’s Solar Dynamics Observatory on March 12, 2016. The complex overlay of lines can teach scientists about the ways the sun's magnetism changes in response to the constant movement on and inside the sun. Note how the magnetic fields are densest near the bright spots visible on the sun – which are magnetically strong active regions – and many of the field lines link one active region to another.

This magnetic map was created using the PFSS – Potential Field Source Surface – model, a model of the magnetic field in the sun’s atmosphere based on magnetic measurements of the solar surface. The underlying image was taken in extreme ultraviolet wavelengths of 171 angstroms. This type of light is invisible to our eyes, but is colorized here in gold.

lundi 14 mars 2016

NASA launched the Magnetospheric Multiscale, or MMS, mission on March 12, 2015. MMS consists of four identical spacecraft that orbit around Earth through the dynamic magnetic system surrounding our planet to study a little-understood phenomenon called magnetic reconnection. Magnetic reconnection is a fundamental process that happens in space, which powers a wide variety of events, from giant explosions on the sun to green-blue auroras shimmering in the night sky.

Image above: Artist concept of the Magnetospheric Multiscale, or MMS, mission to study how magnetic fields release energy in a process known as magnetic reconnection. Image Credit: NASA.

To celebrate the anniversary of the MMS launch, we're sharing a host of MMS facts from its flawless first year.

- 1 year: Length of time MMS has been in space

- 4: Number of observatories launched together on a single United Launch Alliance Atlas V rocket from Cape Canaveral Air Force Station, Florida, on March 12, 2015.

- 600: Number of people who helped build MMS.

- 8: Total pairs of booms successfully deployed.

- 100: Number of sensors flying on the four MMS observatories — all working perfectly.

- 33: Number of times per second that the Fast Plasma Investigation instrument on board MMS gathers pressure, velocity and temperature observations of the charged particles in space.

Cassini spacecraft captured this view of Saturn's moon Enceladus that shows wrinkled plains that are remarkably youthful in appearance, being generally free of large impact craters.

When viewed with north pointing up, as in this image, the day-night boundary line (or terminator) cuts diagonally across Enceladus, with Saturn approaching its northern summer solstice. The lit portion on all of Saturn's large, icy moons, including Enceladus (313 miles or 504 kilometers across) and Saturn itself, is now centered on their northern hemispheres. This change of season, coupled with a new spacecraft trajectory, has progressively revealed new terrains compared to when Cassini arrived in 2004 (see PIA06547), when the southern hemisphere was more illuminated.

This view looks toward the leading hemisphere of Enceladus. The image was taken in green light with the Cassini spacecraft narrow-angle camera on Jan. 14, 2016.

The view was acquired at a distance of approximately 49,000 miles (79,000 kilometers) from Enceladus. Image scale is 1,540 feet (470 meters) per pixel.

The Cassini mission is a cooperative project of NASA, ESA (the European Space Agency) and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colorado.

Image above: ExoMars 2016 lifted off on a Proton-M rocket from Baikonur, Kazakhstan at 09:31 GMT on 14 March 2016.

The ExoMars 2016 mission launches at 09:31 GMT (10:31 CET) on 14 March from Baikonur Cosmodrome in Kazakhstan on a powerful Proton rocket, marking the start of a seven-month cruise to the Red Planet.

ExoMars 2016 liftoff

ExoMars is a joint endeavour between ESA and Russia’s Roscosmos space agency, and comprises the Trace Gas Orbiter (TGO) and the Schiaparelli entry, descent and landing demonstrator.

TGO will make a detailed inventory of Mars’ atmospheric gases, with particular interest in rare gases like methane, while Schiaparelli will demonstrate a range of technologies to enable a controlled landing on Mars for the 2018 rover mission.

Schiaparelli separating from Trace Gas Orbiter

Image above: Artist’s impression depicting the separation of the ExoMars 2016 entry, descent and landing demonstrator module, named Schiaparelli, from the Trace Gas Orbiter, and heading for Mars.

ExoMars 2016 Schiaparelli descent sequence

Image above: Overview of Schiaparelli’s entry, descent and landing sequence on Mars, with approximate time, altitude and speed of key events indicated.

Schiaparelli is scheduled to separate from TGO on 16 October 2016, three days before arriving at Mars. Twelve hours after separation, the TGO will perform a course correction to avoid entering the atmosphere, and will continue into Mars orbit. Then, on 19 October, Schiaparelli will enter the atmosphere at an altitude of about 121 km and a speed of nearly 21 000 km/h. In the three to four minutes that follow, it will be slowed by the increasing atmospheric drag, with the front shield of the aeroshell bearing the brunt of the heating.

This will slowly melt and vaporise, allowing the absorbed heat to be carried away from the rest of the spacecraft. Once the speed has decreased to around 1700 km/h Schiaparelli will be 11 km above the surface and a parachute will be deployed. The parachute canopy will unfurl in less than a second, and, 40 seconds later, allowing for oscillations to die down, the front shield of the aeroshell will be jettisoned. The parachute will slow Schiaparelli to around 250 km/h, and then the back half of the aeroshell, with the parachute attached to it, will also be jettisoned.

ExoMars Trace Gas Orbiter

It will be drawn rapidly away from Schiaparelli, which will now be completely free of the aeroshell that had kept it safe en route to Mars. Schiaparelli will then activate its three hydrazine thrusters to control its speed. Radar will continuously measure the height above the surface. At an altitude of around 2 m, Schiaparelli will briefly hover before cutting its thrusters, leaving it to free fall. The touchdown speed will be a few metres per second, with the impact absorbed by a crushable structure similar to the crumple zone in a car, on the underside of the lander, preventing damage to the rest of the module. The entire entry, descent and landing sequence will be complete in less than six minutes.